You're in the right ball park but I might argue a little with the answer. If we call lactic acid, HL, then
...........HL ==> H^+ + L^-
initial...0.10.....0.....0
change.....-x.....x.....x
final.....0.1-x...x.....x
For pH 2.44 I obtained 0.00363 and substituted
(0.00363)(0.00363)/(0.10-0.00363) = Ka
For which I obtained 1.368E-4 which would round to 1.4E-4 to two s.f.